Plant community and diversity change due to localized permafrost dynamics in bogs of western Canada

2001 ◽  
Vol 79 (8) ◽  
pp. 983-993 ◽  
Author(s):  
David W Beilman

Localized permafrost formation and melt at the southern limit of permafrost has a large effect on boreal bog plant community structure and diversity in continental western Canada (Alberta, Saskatchewan, and Manitoba). Non-metric multidimensional scaling ordinations show that non-permafrost-affected bogs, areas currently underlain by permafrost (frost mounds), and areas of permafrost degradation (internal lawns) have distinct plant communities. Bryophytes respond more strongly than vascular plants to lengthened environmental gradients in the bogs studied. Seventy-two vascular plant and bryophyte species were found, with mean alpha diversity (species richness) similar in bogs and internal lawns (22.6 and 22.1) and lowest on frost mounds (15.6). Beta diversity (species turnover between landforms) is greater for bryophytes (4.22) than vascular plants (2.54). Comparisons within internal lawns show highly variable height above water table, community composition, and species diversity in wet communities and reduced variability as peat accumulates and converges on dry surfaces dominated by Sphagnum fuscum (Schimp.) Klinggr. Overall, localized permafrost dynamics increase bog plant diversity by 47% by introduction of unique dry, shaded (frost mound) and wet, open (internal lawn) conditions absent from non-permafrost-affected bogs, making localized permafrost bogs one of the most bryologically diverse peatland types in western Canada.Key words: peatlands, bryophytes, plant communities, non-metric multidimensional scaling ordination, permafrost, climate change.


1989 ◽  
Vol 67 (4) ◽  
pp. 1126-1136 ◽  
Author(s):  
M. Muc ◽  
B. Freedman ◽  
J. Svoboda

A cluster analysis was used to apportion 136 stands in a High Arctic lowland among six vascular plant community types. These communities are described on the basis of the average prominence values of vascular species and the total cover of macroalgae, bryophytes, lichens, and vascular plants within the designated clusters of stands. The relationships among the community types was explored by a detrended correspondence analysis. The ordination of stands showed considerable floristic overlap among the most widespread plant communities on the lowland. This largely reflects the microtopographic heterogeneity of the sites, the relatively depauperate flora of the High Arctic, and the considerable ecological amplitude of the most prominent vascular plant species.



Author(s):  
Marju Prass ◽  
Satu Ramula ◽  
Miia Jauni ◽  
Heikki Setälä ◽  
D. Johan Kotze

AbstractThe ecological impacts of invasive species may change or accumulate with time since local invasion, potentially inducing further changes in communities and the abiotic environment. Yet, time since invasion is rarely considered when investigating the ecological impacts of invasive non-native species. To examine the effect of time since invasion on the ecological impacts of Lupinus polyphyllus, a perennial nitrogen-fixing herb, we surveyed vascular plant communities in the presence and absence of L. polyphyllus in young, intermediate, and old semi-natural grassland sites (ca. 5, 10, 15 years representing both time since lupine invasion and plant community age). We analyzed vascular plant community composition, vascular plant species richness, and the cover of various ecological plant groups and L. polyphyllus. In contrast to our hypotheses, we found no change in the mean cover of L. polyphyllus (about 35%) with time since local invasion, and an ordination did not suggest marked changes in plant community composition. L. polyphyllus was associated with lower species richness in invaded plant communities but this effect did not change with time since invasion. Invaded plant communities were also associated with lower occurrence of generalist, oligotrophic (low-nutrient-adapted) and copiotrophic (nutrient-demanding) species but no temporal dynamics were detected. We conclude that even the intermediate cover of L. polyphyllus can reduce plant species richness, but the ecological impact caused by this invader might not dramatically change or accumulate with time since invasion.



1982 ◽  
Vol 60 (8) ◽  
pp. 1447-1460 ◽  
Author(s):  
Neil K. Dawe ◽  
Eric R. White

Nine vascular plant communities were determined and mapped from data gathered on the Little Qualicum River estuary, Vancouver Island, B.C., during the period May to September 1978. Those communities comprised 51 species of vascular plants; however, only 10 species occurred with constancies of 20% or greater. Carex lyngbyei, Potentilla pacifica, Juncus balticus, and Agrostis sp. dominated vegetation. Major factors affecting the distribution of the vegetation within the estuary appeared to be site elevation, soil type and texture, and inundating water salinity. Aerial production was dominated by that of the Carex – channel edge community which had a peak aboveground biomass of 1693 g dry weight∙m−2.



1980 ◽  
Vol 58 (20) ◽  
pp. 2148-2170 ◽  
Author(s):  
Marianne G. See ◽  
L. C. Bliss

Alpine lichen-dominated vegetation is described with emphasis upon floristic composition, quantitative structure, and distribution of lichen communities. Macrolichens and vascular plants were quantitatively sampled using stratified random quadrats (10 cm × 40 cm) in 40 stands (30 m × 5 m) in west-central Alberta and north central Yukon Territory. Comparable acid and basic substrates, and glaciated and unglaciated sites were sampled in each region. Bray-Curtis and reciprocal averaging ordinations were used to analyze vegetation data. For both macrolichens and vascular plants, floristic similarity is greater within each region than on equivalent substrates in different regions. Three alpine macrolichen communities are described in each region which exhibit pronounced regional differences. Cetraria tilesii and Thamnolia subuliformis characterize driest sites in both regions, while Cetraria cucullata indicates mesic habitats. Cladonia spp. dominate acidic Yukon sites; Stereocaulon alpinum and Peltigera aphthosa characterize equivalent Alberta habitats. Vascular plant communities are dominated by Dryas integrifolia and D. octopetala in Alberta and Yukon areas, respectively, with dwarf willow and heath in acidic, mesic sites. Distribution of alpine communities of macrolichens and corresponding vascular plants is more strongly correlated with substate pH and moisture, than with glaciation history. Comparison with other northern studies suggests that these macrolichen communities may be found throughout the Canadian Cordillera where equivalent habitats are present.



2020 ◽  
Author(s):  
Antoine Becker-Scarpitta ◽  
Diane Auberson-Lavoie ◽  
Mark Vellend

Abstract1: Despite many studies showing biodiversity responses to warming, the generality of such responses across taxa remains unclear. Very few studies have tested for evidence of bryophyte community responses to warming, despite the fact that bryophytes are major contributors to diversity in many ecosystems, playing a central role in ecosystem functions. Understanding variation among taxa in their responses to warming is crucial for identifying priorities in conservation.2: We report an empirical study comparing long-term change of bryophyte and vascular plant communities in two sites with contrasting long-term warming trends. To assess long-term responses of ecological communities to warming, we used “legacy” botanical records as a baseline for comparison with contemporary resurveys.We hypothesized that ecological changes would be greater in sites with a stronger warming trends, and that vascular plant communities would be more sensitive than bryophyte communities to climate warming. For each taxon in each site, we quantified the magnitude of changes in species’ distributions along the elevation gradient, species richness, and community composition.3: Temporal changes in vascular plant communities were consistent with the warming hypothesis, but this was not the case for bryophytes. We also did not find clear support for the hypothesis that vascular plants would show greater sensitivity than bryophytes to warming, with results depending on the metric of community change. As predicted for sites with a strong warming trend, we found a significant upward shift in the distributions of vascular plants but not bryophytes.Synthesis: Our results are in accordance with recent literature showing that local diversity can remain unchanged despite strong changes in composition. Regardless of whether one taxon is systematically more or less sensitive to environmental change than another, our results suggest that vascular plants cannot be used as a surrogate for bryophytes in terms of predicting the nature and magnitude of responses to warming. In sites that experienced the same environmental changes, we found that communities of bryophytes and vascular plants did not predictably change in the same ways. Thus, to assess overall biodiversity responses to global change, data from different taxonomical groups and community properties need to be synthesized.



PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6347 ◽  
Author(s):  
Tobias Roth ◽  
Lukas Kohli ◽  
Christoph Bühler ◽  
Beat Rihm ◽  
Reto Giulio Meuli ◽  
...  

Nitrogen (N) deposition is a major threat to biodiversity in many habitats. The recent introduction of cleaner technologies in Switzerland has led to a reduction in the emissions of nitrogen oxides, with a consequent decrease in N deposition. We examined different drivers of plant community change, that is, N deposition, climate warming, and land-use change, in Swiss mountain hay meadows, using data from the Swiss biodiversity monitoring program. We compared indicator values of species that disappeared from or colonized a site (species turnover) with the indicator values of randomly chosen species from the same site. While oligotrophic plant species were more likely to colonize, compared to random expectation, we found only weak shifts in plant community composition. In particular, the average nutrient value of plant communities remained stable over time (2003–2017). We found the largest deviations from random expectation in the nutrient values of colonizing species, suggesting that N deposition or other factors that change the nutrient content of soils were important drivers of the species composition change over the last 15 years in Swiss mountain hay meadows. In addition, we observed an overall replacement of species with lower indicator values for temperature with species with higher values. Apparently, the community effects of the replacement of eutrophic species with oligotrophic species was outweighed by climate warming. Our results add to the increasing evidence that plant communities in changing environments may be relatively stable regarding average species richness or average indicator values, but that this apparent stability is often accompanied by a marked turnover of species.



1997 ◽  
Vol 75 (10) ◽  
pp. 1785-1805 ◽  
Author(s):  
Dennis S. Anderson ◽  
Ronald B. Davis

This study is based on relevés from 96 peatlands representing the typologic, environmental, and geographic variation of Maine peatlands, and on peat pore-water chemistry at a representative set of 51 of these peatlands. We give optima and tolerances of pH, Ca, P, NO3-N, NH4-N, and influence of upper on lower vegetational strata for the 73 most common vascular plant species, excluding sedges, which are presented elsewhere. The program TWINSPAN differentiated 30 plant communities. Environments of the first seven TWINSPAN divisions differed largely by Ca, pH, P, NH4, Fe, microrelief, substrate depth, degree of humification, and climate. A canonical correspondence analysis (CCA) with forward selection entered pH, P, Na, Fe, Ca, Mg, and percent H2O as the minimum number of variables which best explains species variation. A CCA of the lower strata vascular plants demonstrated the importance of the upper strata (percent overstory) on species' distributions. Gradients of pH–alkalinity and percent overstory are primary in determining Maine's peatland vegetation. Other important gradients are percent H2O in upper peat, concentrations of lithic elements (P, Fe, Mn, Al, and Si) in pore water, and climate. Although these gradients partially covary, some of the variation in species' distributions can be attributed to independent aspects of individual gradients. Species richness across the range of peatland types is related to pH–alkalinity for vascular plants, and to percent H2O, microrelief, and percent overstory for bryophytes. Key words: plant communities, Maine, multivariate statistical analysis, peatlands, mires, vegetation.



2018 ◽  
Author(s):  
Tobias Roth ◽  
Lukas Kohli ◽  
Christoph Bühler ◽  
Beat Rihm ◽  
Reto Giulio Meuli ◽  
...  

Nitrogen (N) deposition is a major threat to biodiversity in many habitats. The recent introduction of cleaner technologies in Switzerland has led to a reduction in the emissions of nitrogen oxides, with a consequent decrease in N deposition. We examined different drivers of plant community change, i.e. N deposition, climate warming, and land-use change, in Swiss mountain hay meadows, using data from the Swiss biodiversity monitoring program. We compared indicator values of species that disappeared from or colonized a site (species turnover) with the indicator values of randomly chosen species from the same site. While oligotrophic plant species were more likely to colonize, compared to random expectation, we found only weak shifts in plant community composition. In particular, the average nutrient value of plant communities remained stable over time (2003-2017). We found the largest deviations from random expectation in the nutrient values of colonizing species, suggesting that N deposition or other factors that change the nutrient content of soils were important drivers of the species composition change over the last 15 years in Swiss mountain hay meadows. In addition, we observed an overall replacement of species with lower indicator values for temperature with species with higher values. Apparently, the community effects of the replacement of eutrophic species with oligotrophic species was outweighed by climate warming. Our results add to the increasing evidence that plant communities in changing environments may be relatively stable regarding average species richness or average indicator values, but that this apparent stability is often accompanied by a marked turnover of species.



2006 ◽  
Vol 36 (9) ◽  
pp. 2131-2140 ◽  
Author(s):  
John M Hagan ◽  
Sacha Pealer ◽  
Andrew A Whitman

Defining riparian zones is important because sustainable forestry programs typically include a requirement to protect riparian zones. To help determine whether small first-order headwater streams have a riparian zone, we surveyed vascular plant communities along 15 streams in a managed forest landscape in western Maine, USA. Along each stream we recorded all vascular plant species in 5 m × 50 m quadrats at different lateral distances from the stream bank: 0–5, 13–18, 25–30, and 40–45 m. Trees and shrubs showed no statistical differences among zones in either species richness or community composition. Species richness of herbaceous plants was greater in the 0-5 m zone adjacent to the stream bank than in other zones, and species composition of herbaceous plants was statistically different in the 0–5 m zone relative to more distant zones. Twenty-four herbaceous species (of 129) were determined to be indicators of the riparian plant community. Twenty-three of the 24 indicator species were more likely to occur near the stream, and 1 species was more likely to be found away from the stream (a negative riparian indicator). These results show that a narrow riparian zone exists on small headwater streams that is reflected by the herbaceous plant community.



Author(s):  
S.V. Krylenko ◽  
A.I. Lukinykh

Abrasion coasts (cliffs) are characterized by heterogeneity of the spatial structure and mobility of the substrate, which creates specific environmental conditions for plants. Nevertheless, plant communities of cliffs of the Black Sea coast of the Northwestern Caucasus are well developed due to the presence of a large number of Mediterranean species that are well adapted to such conditions. Communities are also supplemented by local endemics and representatives of petrophytic vegetation of adjacent areas. As a result, a specific plant community is formed on the cliff, represented by species from different floristic areas. Thus, the aim of this work was to analyze the species composition of higher vascular plants of the abrasion shore area of the Black Sea coast of the Northwestern Caucasus. On the studied cliff, 131 species of vascular plants were found, including 5 Crimean-Novorossiysk and 6 Novorossiysk endemic, as well as 6 species found in the Red List of the Russian Federation. Extreme unevenness in the density distribution of vegetation was noted, which may be due to the heterogeneity of the relief and the mobility of the substrate. Analysis of supraspecific taxa (families) showed the predominance of representatives of the Apiaceae, Fabaceae, and Poaceae families in the plant community. In addition, chorological analysis of vascular plant species was performed. The data of the performed chorological analysis confirm the relation of the studied territory to the Crimean Novorossiysk province. Thus, despite the specific environmental conditions, the plant community of the studied cliff is rich in species, including endemic species.



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